Load following in a deregulated power system with Thyristor Controlled Series Compensator

Load following is considered to be an ancillary service in a deregulated power system. This paper investigates the effect of a Thyristor Controlled Series Compensator (TCSC) for load following in a deregulated two area interconnected thermal system with two GENCOs and two DISCOs in either areas. Optimal gain settings of the integral controllers in the control areas are obtained using Genetic Algorithm by minimizing a quadratic performance index. Simulation studies carried out in MATLAB validates that a Thyristor Controlled Series Compensator in series with tie-line can effectively improve the load following performance of the power system in a deregulated environment.     

State estimation of power systems containing facts controllers

This paper proposes a practical approach to incorporate Flexible AC Transmission Systems (FACTS) devices into a Weighted Least Squares (WLS) state estimation algorithm. The FACTS devices included in the estimator are the Thyristor Controlled Series Compensator (TCSC), the Static Var Compensator (SVC), and the Unified Power Flow Controller (UPFC). The proposed approach simultaneously upgrades the estimated values of the state variables of these devices and the state variables of the rest of the electric network, for a unified solution in a single-frame of reference. Results are presented to demonstrate the effectiveness of the proposed approach to assess the estimation of the system state and to set the parameters of FACTS controllers for given control specifications.     

用于提高暂态稳定性的可控串联补偿电容器非线性控制器

本文应用直接大范围线性化的方法设计了晶闸管 可控串联补偿电容器非线性控制器,并以单机无穷大系统为例进行了仿真试验。仿真结果表明,所提出的控制方法可以提高系统的暂态稳定性,并能较好地适应系统运行方式的变化。     

FACTS对电力系统静态安全性影响评价指标体系研究

针对目前评价灵活交流输电系统（FACTS）系统稳态性能影响指标的不足,结合FACTS设备自身控制潮流和电压的工作特性,提出了一套全面评估FACTS设备对系统静态安全性影响的指标体系。建立了基于运行状况的晶闸管控制串联电容器（TCSC）、静止无功补偿器（SVC）、统一潮流控制器（UPFC）可靠性模型,并基于该模型提出了FACTS设备的控制策略,该策略以状态量越限值最小为控制目标。建立了采用蒙特卡罗仿真的概率评估算法。通过IEEE-57节点的计算验证了所提指标体系和算法的有效性。     

A non-dominated Sorting Hybrid Cuckoo Search Algorithm for multi-objective optimization in the presence of FACTS devices

In this paper, a proposed Non-dominated Sorting Hybrid Cuckoo Search Algorithm (NSHCSA) for multi objective optimal power flow problem with FACTS devices namely Thyristor Controlled Series Compensator (TCSC) and Static Synchronous Series Compensator (SSSC) with different objective functions including the installation cost of FACTS devices are presented. The practical and operating constraints are considered for this analysis. The location of the FACTS device is selected to enhance the system security with respect to minimizing line overloads and bus voltage violations. The proposed Hybrid Cuckoo Search Algorithm (HCSA) is the combination of Cuckoo Search Algorithm (CSA) and Genetic Algorithm (GA). For multi objectives selected Pareto front is obtained by using the fuzzy decision making tool. The effectiveness of the proposed method is tested on standard IEEE-30 bus test system in the presence of the TCSC and SSSC. The results are analyzed and compared with existing methods.     

大功率电力电子装置过电压保护技术综述

概要回顾和比较了几种常用于电力系统高压装置中的传统过电压保护设备如保护间隙、阀型避雷器和无间隙氧化锌避雷器等;简单叙述了无间隙氧化锌避雷器和晶闸管各自的过电压保护特点。在了解国内外一些大功率电力电子装置如直流输电装置、静止无功补偿装置、可控串联补偿装置等过电压保护技术发展现状的基础上,从电力电子装置本身的过电压保护技术,用电力电子技术对其他设备进行过电压保护两个方面,论述了当今大功率电力电子装置过电压保护的一些措施及其分类。最后,对大功率电力电子装置过电压保护技术进行总结和展望。     

Optimal placement and parameter setting of SVC and TCSC using PSO to mitigate small signal stability problem

This paper aims to select the optimal location and setting parameters of SVC (Static Var Compensator) and TCSC (Thyristor Controlled Series Compensator) controllers using PSO (Particle Swarm Optimization) to mitigate small signal oscillations in a multimachine power system. Though Power System Stabilizers (PSSs) associated with generators are mandatory requirements for damping of oscillations in the power system, its performance still gets affected by changes in network configurations, load variations, etc. Hence installations of FACTS devices have been suggested in this paper to achieve appreciable damping of system oscillations. However the performance of FACTS devices highly depends upon its parameters and suitable location in the power network. In this paper the PSO based technique is used to investigate this problem in order to improve the small signal stability. An attempt has also been made to compare the performance of the TCSC controller with SVC in mitigating the small signal stability problem. To show the validity of the proposed techniques, simulations are carried out in a multimachine system for two common contingencies, e.g., load increase and transmission line outage. The results of small signal stability analysis have been represented employing eigenvalue as well as time domain response. It has been observed that the TCSC controller is more effective than SVC even during higher loading in mitigating the small signal stability problem.     

A new method for secured optimal power flow under normal and network contingencies via optimal location of TCSC

In the deregulated power industry, private power producers are increasing rapidly to meet the increase demand. The purpose of the transmission network is to pool power plants and load centers in order to supply the load at a required reliability, maximum efficiency and at lower cost. As power transfer increases, the power system becomes increasingly more difficult to operate and insecure with unscheduled power flows and higher losses. FACTS devices such as Thyristor Controlled Series Compensator (TCSC) can be very effective to power system security. Proper location of TCSC plays key role in optimal power flow solution and enhancement of system performance without violating the security of the system. This paper applied min cut algorithm to select proper location of TCSC for secured optimal power flow under normal and contingencies operating condition. Proposed method requires a two-step approach. First, the optimal location of the TCSC in the network must be ascertained by min cut algorithm and then, the optimal power flow (OPF) with TCSC under normal and contingencies operating condition is solved. The proposed method was tested and validated for locating TCSC in Six bus, IEEE 14-, IEEE-30 and IEEE-118 bus test systems. Results show that the proposed method is good to select proper location of TCSC for secured OPF.     

Selection of TCSC location for secured optimal power flow under normal and network contingencies

This paper focuses on the optimal power flow solution and enhancement of system performance without sacrificing the security of the system via optimal location and optimal sizing of Thyristor Controlled Series Compensator (TCSC) when the system is operating under normal and network contingency conditions. The paper presents a secured optimal power flow solution by integrating TCSC with the optimization model developed under normal and contingency cases. The optimization model developed in this paper is solved by using linear programming method. New indices called Thermal Capacity Index (TCI) and Contingency Capacity Index (CCI) are proposed for placing the TCSC at appropriate location under normal and network contingency conditions respectively. Once the location to install TCSC is identified, the optimal setting of TCSC is determined through the software code written in MATLAB. The proposed approach is carried out on 6-bus, IEEE 14-bus and IEEE 118-bus test systems and the simulation results are presented to validate the proposed method.     

TCSC与SSSC的特性仿真分析

对基于晶闸管控制的可控串联补偿电容器和基于可关断器件GTO控制的静止同步串联补偿器在模块结构、伏安特性、功角特性及等值阻抗特性等方面进行了详细地分析比较,得出结论并进行了仿真验证。     

Improved fault analysis technique for protection of Thyristor controlled series compensated transmission line

Transmission lines are major component of a power system. Any fault on them results in outage of power not only in the area fed by them but also in the neighboring area as well. Therefore, protection of them is very important. Nowadays, in order to allow maximum power transfer series compensation both uncontrolled and controlled are used. Due to the introduction of compensating devices the protection methodology of transmission lines requires changes. A new transmission line fault analysis method based on half cycle post fault three-phase current data has been presented in this paper for series compensated transmission line equipped with Thyristor Controlled Series Compensator (TCSC). The proposed two-step methodology has been developed with the help of Discrete Wavelet Transform (DWT) and implementation of Chebyshev Neural Network (ChNN). ChNN is derived from regular neural network, but is functionally superior. The performance of the developed algorithm has been tested over a vast fault pattern data set dynamically generated with EMTDC/PSCAD. The results with extensive testing indicate effectiveness of the developed scheme with higher level of accuracy and speed. The algorithm is capable of doing classification with minimal training.     

A robust adaptive LQG/LTR TCSC controller applied to damp power system oscillations

This paper investigates the use of self-tuning Linear Quadratic Gaussian control with Loop Transfer Recovery (LQG/LTR), applied in Thyristor Controlled Series Capacitors (TCSC) installed in interconnected power systems. The proposed robust adaptive controller can improve power system stability margins, damping properly the system's dominant electromechanical modes. Although this TCSC controller is designed mainly to identify and damp inter-area modes, it does not affect negatively the local modes damping, therefore enhancing the overall system performance. The proposed controller properties can be verified using non-linear simulations for a four-machine power system, in different operation conditions.     

TCSC allocation in power systems considering switching loss using MOABC algorithm

This paper is dedicated to investigate the influence of switching losses on Thyristor Controlled Series Compensator (TCSC) optimum allocation in power systems by using a Multi-Objective optimization technique. This allocation is performed with respect to minimization in system cost and voltage deviation as the objectives. For this purpose, cost of active power losses, investment cost of devices and active power generation cost in the peak load are considered to constitute the cost function as the economical objective. In addition, the paper considers interest rate in cost calculations to avoid impractical allocation results and imprecise solutions. The operational, technical and controlling constraints as well as load constraints are regarded in the allocation procedure. Also, the simulations are utilizing three unequal annual load levels to find optimum location and size of TCSC. The IEEE-14 Bus test system is used to validate the proposed method and show the importance of TCSC switching loss. Here, a novel optimization algorithm, Multi-Objective Artificial Bee Colony, is presented to provide Pareto optimal solutions. Also, an approach based on the goal attainment method combined with Genetic Algorithm is used to compromise between contradictory objectives and approach to the global optimum.     

配电网TCSC建模及接地故障仿真研究

可控串联补偿技术（Thyristor Controlled Series Compensation,TCSC）作为柔性交流输电系统（Flexible AC Transmission Systems,FACTS）的重要组成部分,是近年来串联补偿技术的代表,也是未来输电系统的支撑技术,其经济性、实用性的特点使其具有较好的应用前景。本文将TCSC应用到配电网系统当中,文中首先介绍了TCSC的基本原理与数学模型,然后基于Matlab/Simulink软件建立配电网系统下的TCSC模型,并以某10kV配电网系统为例,进行接地故障仿真。通过仿真结果证明用该方法建立含TCSC的配电网系统的有效性,为配电网系统下的TCSC的进一步研究提供了理论基础。     

可控串联补偿器暂态稳定的迭代自学习控制(ILC)

介绍了迭代自学习控制的原理,将其用于ＦＡＣＴＳ为暂态稳定控制;比较了固定串补、ＰＩ控制和迭代自学习控制的可控串补对系统暂态稳定的影响;指出迭代自学习控制具有一系列常规控制算法所没有的优点,是值得进一步深入的控制方法。     

Genetic algorithm-based fuzzy multi-objective approach to congestion management using FACTS devices

This paper investigates a novel optimization-based methodology for placement of Flexible AC Transmission Systems (FACTS) devices in order to avoid congestion in the transmission lines while increasing static security margin and voltage profile of a given power system. The optimizations are carried out on the basis of location, size, and number of FACTS devices. Thyristor Controlled Series Compensator (TCSC) and Static Var Compensator (SVC) are two FACTS devices which are implemented in this investigation to achieve the determined objectives. The problem is formulated according to Sequential Quadratic Programming (SQP) problem in the first stage to accurately evaluate static security margin with congestion alleviation constraint in the presence of FACTS devices and estimated annual load profile. In the next stage a Genetic Algorithm (GA)-based fuzzy multi-objective optimization approach is used to find the best trade-off between conflicting objectives. The IEEE 14-bus test system is selected to validate the proposed approach.     

Real-time coordinated optimal facts controllers

A coordinated optimal (CDO) controller is designed to implement multiple Thyristor Controlled Series Compensation (TCSC) devices in a transmission network of interconnected power systems. The proposed controller is utilized to damp inter-area oscillations and to enhance power system damping during large disturbances. The effectiveness of the CDO controller to properly control such devices is demonstrated for a two-machine power system through real-time digital simulation studies using a PSCAD/RTDS.     

电力电子装置高压阀的电介质试验

我国的电力发展战略需要大量使用电力电子装置,电网的安全稳定运行要求电力电子装置在投入前必须进行严格的试验。电力电子装置高压阀是电力电子装置的核心部件,也是最脆弱的环节,是试验的重点。为此介绍了大功率电力电子装置阀(SVC阀、TCSC阀、STATCOM阀和HVDC阀等)的电介质试验,包括IEC标准对试验的要求、试验装置、仪器、局部放电测量方法、测量仪器等。以莱阳钢厂晶闸管控制电抗器(TCR)型静止无功补偿(SVC)工程为例介绍了试验方法在实际工程中的具体应用,给出了试验波形。工程应用的结果证明了试验方法的实用性和有效性。     

TCSC自适应逆推控制器设计

针对可控串联补偿器TCSC(Thyristor Controlled Series Compensator)的动态过程和发电机阻尼系数不能精确测量的情况，将含有TCSC的单机无穷大系统用一个三阶微分方程表示，用自适应逆推方法设计了TCSC稳定控制器。在系统模型中考虑了TCSC的动态过程．同时保留了系统的非线性特性，运用自适应增益控制律进行参数的实时估计。仿真结果表明设计的TCSC稳定控制器能快速抑制振荡，保证单机无穷大系统的暂态稳定。     

描述可控串补装置暂态特性的数学模型

用拓扑建模法建立了能描述可控串补暂态全过程的数学模型,得出暂态响应时间计算公式。通过该模型可了解可控串补的暂态机理,分析响应时间的影响因素,可分析装置参数对暂态特性的影响,数字仿真证明了所建模型的正确性。此外,文中所用的分析方法对同类型电路的建模和特性分析有一定的参考意义,并可为优化可控串补的控制提供模型模拟。